The invention relates to a method for shaping strip-like films and to a plant for carrying out the method.
A material exchange column with a structured packing is known from WO 97/16247 which is built up of packing elements which are arranged one above the other and which in each case have a cross channel structure, with the channels in an upper and a lower edge zone of a packing element of this kind being formed with a special shape. As a result of the special shaping of the packing element a reduced flow resistance results for a gas which flows through the packing and which passes from one packing element to an adjacent one.
It is an object of the invention to create a method with which films can be suitably shaped so that the named packings can be manufactured with the named films. In the following the term xe2x80x9cstrip-like filmxe2x80x9d will be understood to mean any material strip which can be shaped in accordance with the method in accordance with the invention. A material strip of this kind can for example also consist of a wire mesh or of an expanded metal.
The method for the shaping of strip-like films (2), in particular for structured packings, comprises the following steps:
a) A film strip is continuously forwarded from a film supply to shaping units,
b) The film strip is pleated in a first shaping unit. In this, edges are produced which form an angle of inclination to the edges of the film strip having a constant value.
c) After a forwarding of the pleated strip to at least one further shaping unit the latter is reshaped in one or more steps. In this the edges are eliminated through plastic deformation by means of a roller pair in edge zones outside of a middle zone of the strip and are at the same time replaced by curved edges. The angles of inclination of the curved edges continuously increase from the middle zone to the strip edges.
The invention will be described in the following with reference to the drawings.